In 1987, he and Pawel Traczyk published "Invariants of links of Conway type" (Kobe J. Math. 4, 115−139, 1987), which included a description of what is now called the HOMFLY(PT) polynomial.
polynomial | Degree of a polynomial | Polynomial-time approximation scheme | Monic polynomial | Jones polynomial | Irreducible polynomial | Polynomial-time reduction | polynomial-time approximation scheme | Polynomial | Lagrange polynomial | (Lagrange) polynomial | HOMFLY(PT) polynomial | HOMFLY polynomial | Donaldson's polynomial invariants |